Clinical Characteristics, Histopathological Features, and Clinical Outcome of Methamphetamine-Associated Cardiomyopathy

Abstract

Objectives This study aimed to assess characteristics including endomyocardial biopsy and outcome of patients with methamphetamine (MA)-associated cardiomyopathy in a series of patients treated in Germany. Background MA abuse is an increasing problem worldwide. Methods The cases of 30 consecutive MA-abusing patients with a left ventricular (LV) ejection fraction of <40% and endomyocardial biopsy performed at initial diagnosis were analyzed. Baseline characteristics were collected retrospectively, whereas follow-up was prospective. The primary endpoint was a composite of death, nonfatal stroke, and rehospitalization for heart failure. Results Patients were 30.3 ± 1.9 years of age, predominantly male (93.3%), and highly symptomatic; 83.3% had New York Heart Association functional class III or IV dyspnea. Echocardiography revealed marked LV dilatation (mean LV end-diastolic diameter 67.1 ± 7.4 mm) and impaired LV ejection fraction (mean 19 ± 6%). One-third of the patients had intraventricular thrombi. Endomyocardial biopsy revealed markers of inflammation and fibrosis; the fibrosis correlated with the duration of MA abuse. At follow-up, discontinuation of MA abuse together with medical therapy partially improved cardiac function (LV ejection fraction, 19 ± 6 vs. 43 ± 13; p < 0.001) and symptoms (p = 0.056), whereas patients with continued abuse did not show any improvement. The improvement in cardiac function was independently associated with the extent of fibrosis. The primary endpoint occurred more often in patients with continued MA abuse (57.1% vs. 13.0%; p = 0.037). Conclusions MA-associated cardiomyopathy is characterized by severe heart failure and depressed cardiac function. The extent of myocardial fibrosis seems to predict the recoverability of LV function. Cessation of MA abuse is associated with improvement in cardiac function and symptoms, whereas continued MA abuse leads to ongoing heart failure and worse outcome.